1. Technical Field
The present invention relates to methods and systems for transmitting voltage and current between a source and a load with the use of a magnetic amplifier connectable with the source and the load for voltage and current regulation.
2. Background Art
Methods and systems for transmitting voltage and current between a source and a load are known in the art. One of such methods and systems is disclosed in U.S. Pat. No. 8,605,467. In this patent a converter circuit is disclosed, which includes a transformer having a first side and a second side, a switch coupled to the first side of the transformer, a rectifying diode coupled to the second side of the transformer and to a first output terminal of the converter circuit, a clamping diode coupled to the second side of the transformer, to the rectifying diode, and to a second output terminal of the converter circuit. It may also include a boost section, a flyback section, an active clamp, and an isolated flyback section.
U.S. Pat. No. 8,599,576 discloses equipment and systems for protecting electronics against damage or upsets from electromagnetic pulse (HEMP or EMP), intentional electromagnetic interference (IEMI), and high power RF weapons. This equipment can include a shielding arrangement includes a metallic enclosure having an interior volume defining a protected portion and an unprotected portion separated by an electromagnetically shielding barrier, and having a portal providing access to the protective portion and including an access opening, a shielding cover sized to cover the access opening, and an electromagnetically sealing gasket positioned around a perimeter of the access opening. The shielding arrangement also includes one or more filters positioned at least partially within the unprotected portion and along the electromagnetically shielding barrier to dampen electromagnetic signals and/or power signals outside a predetermined acceptable range. In some cases, waveguides beyond cutoff are included, to provide passage of optical signals or airflow through the enclosure.
U.S. Pat. No. 8,587,284 discloses a power supply, which includes an energy transfer element, a switch, and a controller. The controller includes a modulator, a drive signal generator, a comparator, and a variable current limit generator. The modulator generates an enable signal having logic states responsive to a feedback signal. The drive signal generator either enables or skips enabling a switch of the power supply during a switching period in response to the logic state of the enable signal. The comparator asserts an over current signal to disable the switch if the switch current exceeds a variable current limit. The variable current limit generator sets the variable current limit to a first current limit in response to one logic state of the enable signal and sets the variable current limit to a second current limit if the enable signal transitions logic states and the over current signal is asserted during the switching period.
U.S. Pat. No. 8,582,267 discloses an in-rush current limiting system, which has a fast response time so that it can be used with power supplies that turn on and off rapidly. The system dissipates very little power during the normal mode of operation. This is achieved, in various embodiments, by connecting a regulator in series with a load capacitance and in parallel with the system load.
U.S. Pat. No. 8,570,779 discloses a device for converting an electric current, which has a phase module, which in turn has an alternating current connection and at least one direct current connection connected to an intermediate direct current circuit. The device further has an energy accumulator. A phase modulation path is formed between each direct current connection and each alternating current connection. Each phase modulation path has a series connection of submodules, which each have a power semiconductor. A semiconductor protective device is provided in parallel connection to power semiconductors of each submodule. A control unit actuates the semiconductor protective device, and energy accumulator(s) are equipped for supplying energy to the control unit. The device safely prevents damage from a short circuit on the direct-current side, even when the supply grid is connected, because a direct current connection of each phase module is connected to the intermediate direct current circuit via a direct-current switch.
U.S. Pat. No. 8,564,919 discloses a method and apparatus for detecting an overcurrent condition in a dimmer circuit having two switches, each for controlling power delivered to a load, each switch having a respective anti-parallel diode. The method comprises sensing a voltage drop across one of the anti-parallel diodes, comparing the sensed voltage drop with a reference voltage, and determining that an overcurrent condition exists if the sensed voltage drop exceeds the reference voltage. Also disclosed is a dimmer circuit embodying the method.
U.S. Pat. No. 8,493,052 discloses an apparatus and technique to drive a variable load via transformer secondary winding, where the primary of a transformer is driven at low voltages to provide high-voltage dynamic drive from the secondary to a load. A high-current source is placed in series with both the transformer secondary and load. At least secondary inductance of the transformer, hence impedance, is controlled through core saturation to transition secondary output to the load between high-voltage dynamic drive inductively coupled from the primary, and high-current drive serially connected through the secondary. Switching between high voltage and high current output is accomplished through the transformer; no additional switching devices need exist in the high-voltage path. Broad voltage and current capabilities of the configuration inexpensively improve transient drive of highly reactive loads.
U.S. Pat. No. 8,482,944 discloses an inrush protection circuit for an electronic ballast for powering HID lamps. A first resistor is positioned along a low potential side of the circuit and a switching element coupled in parallel with the first resistor. Second and third resistors are coupled in series and effective to receive DC input power from a DC source, with a first node between the second and third resistors further coupled to the gate of the switching element. A capacitor is coupled in parallel with the third resistor to provide a smoothed DC voltage to the gate of the switching element. A discharging circuit includes a diode and a fourth resistor coupled in series between the first node and the high potential side of the circuit, and is arranged to conduct discharging current from the capacitor until the voltage across the capacitor discharges below a predetermined voltage after the DC input power is removed from the circuit.
U.S. Pat. No. 8,369,114 discloses a power supply which employs an error detecting circuit to output an error signal when detecting an overvoltage or overcurrent occurred in one of output powers and which also employs a latch trigger circuit to cause the power supply to enter a latch mode when receiving the error signal. The power supply will keep the latch mode when entering the latch mode until the AC power VAC is removed. In addition, the power supply employs the error detecting circuit to provide the accurate safety threshold value by the constant current source with temperature compensation function and stable constant current output.
U.S. Pat. No. 8,164,221 discloses a control apparatus for a controlled series compensator including a plurality of reactance elements each having a rapid switch for connecting and disconnecting the reactance in series with an electric power transmission line. The apparatus also includes a steady state power flow controller. A damping controller is provides on the presence of an oscillation on the transmission line a first reactance insertion on the transmission line having a first duration of time trigged by a time instant that coincides with a peak in the power oscillation.
U.S. Pat. No. 8,000,118 discloses a method for delivering a controlled voltage, which involves, during a first electric pulse delivered to a primary transformer, holding a first switching section open to isolate the controlled voltage, where the first electric pulse creates a first magnetic flux in a core of the primary transformer, and where the first magnetic flux generates a direct current (DC) magnetizing current. The method further involves receiving the controlled voltage from a voltage source using the DC magnetizing current at a first switching section, and upon termination of the first electric pulse, closing the first switching section to deliver the controlled voltage to the primary transformer.
U.S. Pat. No. 7,675,242 discloses an electronic ballast for the operation of a lamp arrangement includes at least one lamp, in particular, a low-pressure discharge lamp and at least one transformer for balancing the lamp currents, whereby the transformer has two windings, provided for one or more lamps of the lamp arrangement. The transformer is embodied as a saturation balancing choke.
U.S. Pat. No. 7,259,544 discloses a method for compensation and symmetrization of a three-phase system with a single-phase. At least one variable inductor for connection to the three-phase system is employed in the method. The inductor's inductance is adjusted to obtain a resistive single-phase load and/or a three-phase load which draws balanced line currents. A device and a system for compensation and symmetrization by means of variable inductors is also provided.
U.S. Pat. No. 6,784,781 discloses an improved reactor and ballast system. The reactor includes a core having an I portion and a rolled portion which forms a core opening, a coil having an electrically insulated coil opening through which the I portion extends, and a spacer between the I portion and an edge of the rolled portion of the core. A portion of the coil extends into the core opening. The ballast system includes a core having a plurality of I portions and a rolled portion which form one or more core openings, a plurality of coils, each coil having an electrically insulated coil opening through which one of the I portions extends, and a plurality of spacers between the I portions and a first edge of the rolled portion and between the I portions and a second edge of the rolled portion. A portion of each coil extends into a corresponding core opening.
U.S. Pat. No. 6,686,826 discloses a transformer which includes a ferrite base plate having ferrite core between two grooves, two or more windings wound around the ferrite core and engaged in the grooves of the ferrite base plate and electrically coupled together and separated from each other, for forming two spaces in the grooves of the ferrite base plate and formed between the windings. One or more conductive panels may be engaged into each of the spaces of the ferrite base plate for reducing the voltage generated by the windings, and for supplying a stabilized electric power source to electric devices.
U.S. Pat. No. 6,642,630 discloses a multi-output switching power supply circuit which produces multiple outputs with increased power source conversion efficiency.
The circuit includes, in place of the rectifying diode and the commutating diode used in the multi-output switching power supply circuit of the prior art, a circuit configuration in which an NMOS for synchronous rectification is combined with a constant-voltage control by a magnetic amplifier. It is not required to use, for example, a radiator to dissipate heat, and hence the system size is reduced and the conversion efficiency is increased, and the system can be easily implemented in a low-voltage multi-output configuration. In a configuration in which a magnetic amplifier is arranged between a secondary winding and an first NMOS for synchronous rectification and a drive circuit for the first NMOS and an second NMOS for synchronous rectification is implemented as a separate winding other than the secondary winding, the first NMOS is not included in a loop to flow a reset current. The magnetic amplifier can conduct constant-voltage control without any influence from the interruption of the control loop when the first NMOS on the rectifying side is turned off.
U.S. Pat. No. 6,490,184 discloses a forward power converter which includes a transformer for transferring an input voltage from a primary side to a secondary side. The secondary side includes a main output voltage loop and at least one auxiliary output loop connected with a magnetic amplifier. A pulse width modulation (PWM) controller controls a switch on the primary side of the transformer for turning on the switch and turning off the main output voltage loop and the auxiliary output voltage loop for storing a magnetizing energy on windings of the secondary side. The magnetic amplifier includes a first and a second magnetization windings controlled by a first and a second control circuits respectively for providing a positive and negative magnetization current to carrying out a bi-directional magnetization process to achieve expanded load range operable for the forward power converter.
U.S. Pat. No. 6,483,726 discloses a flyback power converter which includes a transformer for transferring an input voltage from a primary side to a secondary side. The secondary side includes a main output voltage loop and at least one auxiliary output loop connected with a magnetic amplifier. A pulse width modulation (PWM) controller controls a switch on the primary side of the transformer for turning on the switch and turning off the main output voltage loop and the auxiliary output voltage loop for storing a magnetizing energy on windings of the secondary side. The PWM controller further turns off the switch and turning on the main output voltage loop for providing a main voltage output and for magnetizing the magnetic amplifier connected to the auxiliary output voltage loop. The magnetic amplifier functioning as an auxiliary-loop switch for turning on the auxiliary output voltage loop when the magnetic amplifier is saturated with magnetization and turning off the main voltage output voltage loop for providing an auxiliary output voltage. A time-shared energy transfer mechanism is provided between the main output voltage loop and the auxiliary output voltage loop to fully utilize the entire duty cycle.
U.S. Pat. No. 6,472,827 discloses a push-pull inverter supplied from an inductively current-limited DC voltage source by way of a center-tap on a transformer having significant inductance. This transformer inductance is parallel-coupled with a capacitance means. The inverter is made to self-oscillate through positive feedback provided by way of a saturable current transformer. The inverter frequency is determined by the saturation time of this current transformer, which saturation time is designed to be somewhat longer than the half-cycle period of the natural resonance frequency of the transformer inductance combined with the capacitance means. By controlling the length of this saturation time, the magnitude of the current provided to the fluorescent lamp is controlled, thereby permitting control of the light output in response to changes in the magnitude of the power line voltage.
U.S. Pat. No. 6,154,019 discloses a controllable inductor which comprises at least a tubular core, a main winding surrounding the core and a control winding passing substantially axially through the core. It is adapted for connection to a three phase alternating current network and has for this sake for each phase a main winding for connection to the phase, a core and a control winding, and the control windings of the three phases are electrically connected in series to each other.
U.S. Pat. No. 5,461,555 discloses a converter which is usable as a kind of DC-DC converter and which comprises a transformer for processing an exciting current into an excited current under influence of an inductance value of the transformer, the inductance value is controlled in compliance with a value of the exciting current. The exciting current is controlled by a current control circuit with reference to the excited current so that exciting current is intermittently supplied to the transformer. While the exciting current is absent during intermittent supply to the transformer, the transformer produces the excited current.
U.S. Pat. No. 4,853,611 discloses an inductive component for universal use in any electrical/electronic circuits, whose coefficient of self-induction (L) is independent of the signal, is constant, electrically controllable and can be varied significantly. The component comprises two mutually independent, identical ring-shaped and self-contained ferromagnetic cores which individually carry the partial windings of an induction winding and jointly carry a control winding. The direction of coiling of the windings is such that the magnetic fields produced by currents through the windings are mutually weakened, but in the other core they are reinforced. The component is connected via its induction winding to a controlled circuit, and via its control winding to a controlling circuit, or forms with its windings an element of this circuit. By varying the current via the control winding the controlling circuit controls the value of the coefficient of self-induction for the controlled circuit, a variation range of at least 1:100 being provided.
U.S. Pat. No. 4,737,704 discloses a variable-ratio transformer for arc and plasma setups, comprising a magnetic core made up of a main part composed of two yokes and legs in accordance with the number of phases and an additional part disposed on the side of the yoke of the main part of the magnetic core. The additional part of the magnetic core is made up of a yoke and legs whose number is equal to the number of the legs of the main part, at least one leg being placed with a gap in relation to the first yoke of the main part. The primary winding of each phase comprises two series-connected parts, the first part being located on the main part of the magnetic core, while the second part is located on the additional part thereof. A controlled electronic switch which regulates the load current flowing through the secondary winding of each phase, disposed on the main part of the magnetic core, is connected in parallel to one of the parts of the primary winding of each phase.
U.S. Pat. No. 4,689,592 discloses a single electromagnetic structure comprising a pair of assembled oppositely positioned pot cores, first and second winding means around each of the pedestals of the cores, and a flat magnetically permeable washer-like member positioned between the windings and spaced from the pedestals and the outer annular rim portions of the pot cores to define a pair of air gaps, whereby the apparatus functions like a transformer and an inductor in series with a winding of the transformer.
U.S. Pat. No. 4,460,954 discloses an improved ferroresonant transformer for a ferroresonant power supply, such as may be used for charging storage batteries, is provided by placing damping means, such as a strip of non-magnetic metallic material in an air gap of such a transformer, thereby eliminating the need for a damping resistor in the circuit of the resonant winding of such a transformer, thereby decreasing the size, weight, and cooling requirements of such a transformer and power supply, and allowing a greater electrical energy efficiency to be obtained.
U.S. Pat. No. 4,445,082 discloses a variable ratio transformer constructed around a control transformer comprising: two closed magnetic circuits each constructed around a ferromagnetic core. An alternating current magnetic field circulates in the first core and a direct current magnetic field circulates in the second core. The two circuits are located so as to define at least two common magnetic spaces in which the fields are superposed orthogonally. Around the first core is wound a primary winding, a secondary winding and, for a specific application in a three-phase circuit, a tertiary winding. A conventional transformer can be associated with the control transformer to reduce the load supported by the control transformer. The variable ratio transformer according to the invention can be used as a static balance compensator.
U.S. Pat. No. 4,414,491 discloses a power supply including a high frequency inverter circuit coupled to an electron discharge lamp load through a special purpose transformer. The transformer is wound on a saturable ferromagnetic core structure forming a first magnetic flux path coupling the primary and secondary windings of the transformer and a second shunt magnetic path including an air gap which carries and increasing share of flux as load current increases. The switching of the inverter circuit occurs in response to the partial saturation of the core. Auxiliary windings serially connected with the primary winding of the transformer and wound about the shunt magnetic path enhance the current regulating properties of the supply.
U.S. Pat. No. 4,339,792 discloses a voltage regulator using a saturable transformer which comprises a transformer having a primary and secondary windings, an AC power source for supplying the primary winding a fluctuating alternating current, and a rectifier connected to the secondary winding for rectifying an AC voltage derived therefrom to produce a DC output voltage. The transformer includes a core having four legs and two common portions magnetically joining the four legs, and a control winding supplied with DC control bias from a control circuit. The primary and secondary windings are wound on the first and second legs and the control winding is wound on the first and third legs.
U.S. Pat. No. 4,045,717 discloses a battery charging circuit for charging a battery load characterized by having a substantial effective capacitance, with a transformer connected in a Scott T configuration, the transformer input being adapted for connection to a three phase power line, and the transformer output circuit being in a four phase star configuration for providing a four phase charging circuit. The transformer additionally contains a pair of ferroresonant circuits, each such circuit containing a capacitance selected to cooperate with the capacitance of the battery so as to provide the desired charging characteristic.
U.S. Pat. No. 3,956,683 discloses an automatic taper charging battery charger having a power transformer and a series connected variable reactor, a pair of rectifiers powered by the transformer, a pair of output terminals coupled to one of the rectifiers, a sensing and control circuit powered by the other rectifier and responsive to the voltage of a battery connected to the output terminals for controlling the impedance of the variable reactor and in turn regulating the voltage developed across the power transformer and thereby controlling the current charging rate supplied to the battery.